Production of 3-pyrazolidones



United States Patent PRODUCTION OF S-PYRAZOLIDONES John David Kendall and George Frank Dufiin, llford, England, assignors to llford Limited, Ilford, England, a British company No Drawing. Application August 14, 1953, Serial No. 374,440

Claims priority, application Great Britain August 25, 1952 9 Claims. (Cl. 260-310) This invention relates to the production of 3-pyrazolidones and particularly the substituted 3-pyrazolidones which are generally of value in compound photographic developers.

'According to the present invention a process of producing 3-pyrazolidones comprises reacting a hydrazine of the general formula RNH.NH2, where R is a hydrogen atom or a hydrocarbon group, with an amide of the general Formula I:

III-NH R II The groups R1, R2, R3 and R4 may be hydrogen atoms or lower alkyl groups, e. g. methyl, ethyl, propyl or butyl, or aryl groups, e. g. phenyl or naphthyl, or aralkyl groups, e. g. benzyl. The group R may also be a hydrogen atom or any of the aforesaid hydrocarbon groups but is preferably a phenyl group since the reagent phenyl hydrazine is readily obtainable and the products, the 1-phenyl-3-pyrazolidones, appear to be generally the most useful technically.

The reaction is preferably carried out in anhydrous conditions and in the presence of a strong basic condensing agent. It has been found that the reaction proceeds more easily and completely as the base used is stronger, and for this reason it is preferred to use strong inorganic bases such as the alkali bases. Very strong bases such as the alkali alkoxides are preferred, and the best results are obtained if these are used in equirnolecular proportion to the other reagents or in slight excess over that proportion.

The following examples will serve to illustrate the invention:

EXAMPLE 1 4-metlzyl-1-phenyl-3-pyrazolidone Sodium (3 g.) was dissolved in ethanol (50 cc.) and phenyl hydrazine cc.), and a-methylacrylamide (8.5 g.) added to the solution, which was then refluxed for two hours, during which time ammonia was evolved. The solution was evaporated to dryness under reduced pressure, the residue dissolved in Water (50 cc.) and the resulting solution acidified with glacial acetic acid (7.5 cc.). A crystalline precipitate rapidly deposited and recrystallisation of the solid from carbon tetrachloride yielded colourless plates, m. pt. 135", of pure 4-methyl- 1phenyl-3-pyrazolidone.

EXAMPLE 2 1 -phenyl-3-pyraz0lid0ne Sodium (3.0 g.) was dissolved in ethanol (100 cc.)

2,704,762 Patented Mar. 22, 1955 EXAMPLE 3 1-phenyl-3-pyrazolidone Sodium (2.2 g.) was dissolved in ethanol (72 cc.) and then phenylhydrazine (7.2 cc.) and N-ethylacrylamide (7.2 g.) added to the solution in that order. After refluxing for two hours the solution was evaporated, under reduced pressure, to dryness. The residue was taken up in Water (50 cc.) and acetic acid (5.6 cc.) added. -A

crystalline mass was precipitated almost immediately .which, after filtration and crystallisation from water, gave pure 1-phenyl-3-pyrazolidoneas colourless needles, m. 121.

, EXAMPLE 4 1 :5-diphenyl-3-pyrazolidone Sodium (0.65 g.) was dissolved in ethanol (25 cc.) and cinnamide (3.7 g.) and phenylhydrazine (2.2 cc.) added to the solution which was then refluxed for four ours.

3-pyrazolidone as colourless plates, m. pt. 159 EXAMPLE 5 v 5 :5 -d imethyl-I -phenyl-3-pyraz0lid0ne Sodium (0.84 g.) was dissolved in ethanol (30 cc.) and phenylhydrazine (2.88 cc.) and fizfi-dimethylacryl ethylamide (3.65 g.) addedto the'solution whichwas then refluxed for 15 hours. solution to dryness under reduced pressure, the residue was taken up in water (30 cc.) and acetic acid (2.7 cc.) added. An oil was precipitated which, on lixiviation with benzene, gave a crystalline precipitate. Recrystallisation of this solid from benzene gave 5:5-dimethyl-1-phenyl- 3-pyrazolidone as colourless plates, m. pt. 166.

EXAMPLE 6 5-methyl-1 -phenyl-3-pyrazolidone EXAMPLE 7 1 -p-tolyl-3-pyrazolid0ne From p-tolyl hydrazine and acrylamide in the presence of an excess of sodium ethoxide. The product crystallises from benzene as colourless plates, m. pt. 163 C.

EXAMPLE 8 1 -p-ch l0rphenyl-3-pyraz0lid0ne From p-chlorphenyl hydrazine and acrylamide in the presence of an excess of sodium ethoxide. The product crystallises from benzene as colourless plates, 111. pt.

EXAMPLE 9 1 -p-anisyl-3-pyrazolidone From p-anisyl hydrazine and acrylamide in the presence of an excess of sodium ethoxide. The product crystallises from benzene as colourless needles, m. pt. 146 C.

The solution was evaporated to dryness, the. residue dissolved in water (50 cc.) and acetic acid (2.2. cc.) added. The precipitated solid was filtered off and recrystallised from methanol to give pure 1:5-diphenyl- After evaporation .of' the 3 EXAMPLE A leg-chlorphenylJ-methyl-i-pyrazalidone,

From p-chlorphenyl hydrazine and a-methyl acrylamide. The product crystallises from carbon tetrachloride, as. colourless needles m. pt. 117 C;

whattwe claim is:

lt Aprocess for: the production ot a 3'-pyrazolidone which; comprises heating: a= hydrazine of the general formulaaRNHzNflzwith anamide of the general formula-:

BK R1 Rs 7 CONHR4 where R, R1, R2, RaandzRaaue each selected from the class consisting of, the hydrogen. atom. and methyl, ethyl, propyl, butyl,,phenyl, lnaphtliyl, lienzyl', tolyl', ,chlorplienyl and methoxyphenyl groups.

2AA process for the production. of. a 3'pyrazo1idone comprises. heating phenyl hydrazine with acryl: arm '6;

3;. A; procession the, production of. a 3 pyrazolidone.

i chj comprises; heating, phenyl. hydrazine with an;

N-alkyli ajcrylamidet.

"4'. A process for the production of' a 3'-pyrazolid oner which comprises heating a hydrazine of the general formula RNH.NH2 with an'amid'eofi'the general formula:

class consistingofjthe hydrogen. atom andmethyl', ethyl, propyl; butyl, phenyhnaphthyI; benzyl, tolyl, chlorphenyl and methoxyphenyl'; groups :under substantially anhydrous conditions and in' the presence of a strong basic condens- 'ing agent.

'5. A process for, the, production of a,3,-pyrazolidone which comprises heating phenyl hydrazine with acrylamide undee' substantially: anhydrous conditions: and in thepresenceof a; strong basic. condensing agent.

- 6; A; process for the-production of; a 3-pyrazolitl'one-- which: comprises: heating phenyl: hydrazine with an N alkyl acrylamideund'ersubstantially anhydrous" conditions and in the presence of a strong basic condensing agent:

7. A process for the production of a 3-pyrazolidone which comprisesheating a hydrazine of the general formula RNHNHz with an'amide of the general formula:

Where R, R1, R2, R3 and R4 are each selected from th class consisting of the hydrogen atom andmethyl, ethyl, propyl, butyl, phenyl, naphthyhbenzyl, tolyl', chlorphenyl and methoxyphenyl groups under substantially anhydrous conditions and in the; presence" of at least an equimolecular quantityof alkali alkoxide.

8. A process for the production of' a 3-pyrazolidone which comprises heating phenyl hydrazine with acrylamidev under substantially anhydrous 'conditions and in the presence. ofat least an equimolecular quantity; of

alkali alkoxid'e.

9. A process for the production of a 3-pyrazolidonewhich comprises heating phenyl hydrazinev with an N-alkyl acrylarnide under substantially anhydrous conditions: andin the'presence of atleast an equimolecul'ar quantity of alkali alkoxide.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Spasov et 211.: Chemical Abstracts, vol. 44, p. 1491 (1950). 

1. A PROCESS FOR THE PRODUCTION OF A 3-PYRAZOLIDONE WHICH COMPRISES HEATING A HYDRAZINE OF THE GENERAL FORMULA RNH.NH2 WITH AN AMIDE OF THE GENERAL FORMULA: 